SIMPLE METHODOLOGY TO DETERMINE THE CRITICAL CONTENT OF THE BENTONITE CONSIDERING PART ICLE PORE AND SWELLING OF BENTONITE

Abstract

 Bentonite mixed soil is commonly used as soil liner in landfill. In this paper, a simple method that can determine the critical content of the bentonite is presented. The critical content of the bentonite is defined as the ratio over which addition dose not contribute to decrease the permeability considerably. For this, a concept of macro void ratio that consider the particle pore and swelling ratio of bentonite is described. Then the calculated critical content of the bentonite for four parent soils with different amount of particle pore are compared with the measured critical content of the bentonite from permeability tests. As the results, it is found that the calculated critical contents of the bentonite are well coincident with the measured ones. In the paper, the reason why the value of macro void ratio shows negative for bentonite addition beyond critical content is also discussed based on the results of water absorption tests for compacted bentonite mixed soil.